MEXICO CITY - The Mexican government, angered by a U.S. proposal to extend a wall along the border to keep out migrants, pledged Tuesday to block the plan and organize an international campaign against it.

Facing a growing tide of anti-immigrant sentiment north of the border, the government has taken out ads urging Mexican workers to denounce rights violations in the United States. It also is hiring an American public relations firm to improve its image and counter growing U.S. concerns about immigration.

Mexican President Vicente Fox denounced the U.S. measures, passed by the House of Representatives Friday, as "shameful." His foreign secretary, Luis Ernesto Derbez, echoed his complaints on Tuesday.

"Mexico is not going to bear, it is not going to permit, and it will not allow a stupid thing like this wall," Derbez said.

"What has to be done is to raise a storm of criticism, as is already happening, against this," he said, promising to turn the international community against the plan.

At least 10 million Mexican citizens are believed to be living in the United States. U.S. authorities believe about half of them do not have papers.

In 2004, Mexican migrants north of the Rio Grande sent home more than $16 billion in remittances, according to Mexico's central bank, giving the nation its second biggest source of foreign currency after oil exports.

Some stretches of the U.S.-Mexico border are already marked by fences, but in some heavily trafficked sections walls have already been erected by the United States, often using 10-foot-high sections of military surplus steel. Those sections, which typically run several miles, can be found in southern Arizona and California.

It's hard to underestimate the ill-feeling the proposal has generated in Mexico, where editorial pages are dominated by cartoons of Uncle Sam putting up walls bearing anti-Mexican messages.

Many Mexicans, especially those who have spent time working in the U.S., feel the proposal is a slap in the face to those who work hard and contribute to the U.S. economy.

Fernando Robledo, 42, of the western state of Zacatecas, says the proposals could stem migration and disrupt families by breaking cross-border ties.

"When people heard this, it worried everybody, because this will affect everybody in some way, and their families," Robledo said. "They were incredulous. How could they do this, propose something like this?"

Robledo, whose son and mother are U.S. citizens, predicted the measure "would unleash conflict within the United States" as small businesses fail for lack of workers.

He said many Mexicans felt betrayed by the anti-immigrant sentiment.

"We learned to believe in the United States. We have a binational life," he said of Zacatecas, a state that has been sending migrants north for more than a century. "It isn't just a feeling of rejection. It's against what we see as part of our life, our culture, our territory."

The government is scrambling to fight on two fronts. On Monday, it announced it had hired Allyn & Company, a Dallas-based public relations company to help improve Mexico's image and stem the immigration backlash.

"If people in the U.S. and Canada had an accurate view of the success of democracy, political stability and economic prosperity in Mexico, it would improve their views on specific bilateral issues like immigration and border security," Rob Allyn, president of the PR firm, told The Associated Press Tuesday.

"I would expect more energetic reactions from our authorities," Soberanes told local media. "It's preferable to have a more demanding government, more confrontation with the United States."

Mexico has also said it is recruiting U.S. church, community and business groups to oppose the proposal.

And the government has stepped up its defense of migrants, airing a series of radio spots here aimed at migrants returning home for the holidays.

"Had a labor accident in the United States? You have rights ... Call," reads the ad, sponsored by Mexico's Foreign Relations Department, which has helped migrants bring compensation suits in the United States.

The sense of dread connected with the measures is hardly restricted to Mexico. Immigrant advocacy and aid groups in the United States are worried about provisions of the House bill that upgrade unlawful presence in the United States from a civil offense to a felony.

"It would have a horrific impact on immigrants right organizing and immigrant communities" in the United States, said Jennifer Allen of the Tucson, Ariz.-based Red de Accion Fronteriza.

The mistaken belief that the proposals are a done deal Â they must still be submitted to the Senate Â have caused "just complete fear and shock" among some activists and immigrants, Allen said.

The House bill, passed on a 239-182 vote, includes a proposal to build 700 miles of additional fence through parts of California, Arizona, New Mexico and Texas. It would also enlist military and local law enforcement to help stop illegal entrants and require employers to verify the legal status of their workers.

Mexicans are outraged by the proposed measures, especially the extension of the border wall, which many liken to the Berlin Wall. Some are urging their government to fight it fiercely.

"Our president should oppose that wall and make them stop it, at all costs," said Martin Vazquez, 26, at the Mexico City airport as he returned from his job as a hotel worker in Las Vegas. "More than just insulting, it's terrible."

My first thought is that it is disingenuous to call this an "anti-immigration" policy. It is a policy geared towards stopping criminals from coming into our country. Yes, illegal immigrants are criminals.

They are angry? What in the world do they have to be angry about? All I know is that I am angry that I have to pay my tax money to support illegal immigrants and their children. Oh, and I am sick of doing it.

Okay, I have to say this, Mexico, you have nothing to say about what we erect in our country. Open your pie-hole again and me and three friends are going to come down there with a switch and set y'all straight.